vortex induced vibratio ns aquatic clean energy converter vivace- shaz

VORTEX INDUCED VIBRATIONs AQUATIC CLEAN ENERGY CONVERTER - VIVACE

Shaz muhammad r

Mes COLLEGE OF ENGG:

• The Tacoma narrows bridge incident• Vortex induced vibration• How a fish propels itself in water• The VIVACE• How the vivace works• Why vivace• High utilization expected for vivace• Salient features of vivace• Advantages • References

TOPICS COVERED

The tacoma narrows bridge incident (1940)

November 7, 1940, at 11:00 am (Pacific time)

VORTEX INDUCED VIBRATIONS

• (VIV) are motions induced on bodies facing an external flow by periodical irregularities on this flow.

• They are experienced by any unstable cylindrical objects which may be small car antennas or 120 foot diameter platforms used in off-shore engineering

• Vortex Induced Vibrations (VIV) results from vortices forming and shedding on the downstream side of a bluff body in a current.

• If the frequency of vortex shedding matches the resonance frequency of the structure, the structure will begin to resonate and the structure's movement can become self-sustaining.

• Real fluids always present some viscosity.• Boundary layer will form and thus the flow around

the cylinder will be slowed down while in contact with its surface.

• At some point this boundary layers separate from the body due to its excessive curvature.

• Vortices are then formed changing the pressure distribution along the surface.

• When the vortices are not formed symmetrically around the body, different lift forces develop on either side of the body, thus leading to motion transverse to the flow.

VIV OF A CYLINDER IN FLUID FLOW

Flow over a cylinder

HOW FISHES SWIM IN

WATER

VORTEX INDUCED VIBRATIONS AQUATIC CLEAN ENERGY -VIVACE

• Entails a cylinder that hangs horizontally across the flow of water.

• The cylinders are free to move through the guide ways in the vertical direction

• The cylinder holds a magnet at the end, inside the guide ways.

• A metal coil winding is provided inside the guide ways

CONSTRUCTION

PARTS

HOW THE VIVACE WORKS

THE CONVENTIONAL WIND TURBINE`

• The flow of air across the blades creates lift that turns the rotor of a wind turbine.

• The world’s largest wind farm, the Horse Hollow Wind Energy Center in Texas, generates 735.5 MW at peak power with 291 1.5 MW wind turbines and 130 2.3 MW wind turbines spread over an area of 190 square kilometers.

• The rated wind speed required for this output is 12m/s• The farm occupies a volume of almost 22 cubic

kilometers.

WHY THE VIVACE? Water has a high energy density and is 830 times

denser than air.

The comparable water flow velocity to air velocity of 12m/s is 1.3 m/second.

The Corresponding power density is 185 watts per cubic meter.

The power density of the VIVACE converter is

14,600 times greater than that of the wind farm. Power is generated at a cost of

2.45 RS/KWH

TECHNOLOGY CAPITAL COSTRS/kW

FUEL COSTRS/kWh

CAPACITY FACTOR (%)

COST RS/ kWh

Conventional Generation

PULVARISED COAL 64,664 .495 85% 1.845

NUCLEAR 98,100 .225 90% 2.07

NATURAL GAS 21,015 1.935 45% 2.79

Alternative Generation

WIND 54,000 0.000 25% 3.105

VIVACE 135,000 0.000 90% 2.475

SALIENT FEATURES

• CLEAN ENERGY• DOESN’T DISRUPT THE NATURAL FLORA & FAUNA• NO DAMS OR TURBINES ARE USED• POWER AT 2.75 RS/KWh• CONSISTANT AND RELIABLE POWER GENERATION

THROUGHT THE YEAR.• GENERATES POWER IN WATER CURRENTS OF EVEN 1 KNOTS

(I KNOT=1.85Km/hr)

ADVANTAGES

Has high energy density Is unobtrusive to navigation Is unobtrusive to coastal property Is unobtrusive to marine life Has good robustness Has low maintenance Achieves certain life cycle cost target Have a design life of at least 15-20 years

REFERENCES• ASME JOURNAL (mechanical engineering) - APRIL 2010• www.vortexhydroenergy.com• www.asme.org/vivaceconverter• www.rexresearch.com/bernitsas/bernitsas.htm• www.techtransfer.umich.edu• www.renewableenergyworld.com• memagazine.asme.org/Articles/2010/April/

Out_Vortex.cfm

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